Method of manufacturing lightweight ceramics

Abstract

The present invention discloses a method of manufacturing lightweight ceramics by mixing several raw materials such as a powdered glass material, a powdered alkali silicate, and a water-soluble polymer in a certain proportion to form a dry substrate, and then adding water to mold the substrate into a desired shape; after the water in the substrate is baked dry, heat the substrate until the ceramic is formed. The oxide and hydroxide in the alkali silicate are used to lower the softening point of the powdered glass material, and when the powdered glass material is in the semi fluid state, the air and crystal water brought by the alkali silicate will expand and form air bubbles due to the high temperature. In the meantime, the water-soluble polymer at the high temperature will also be converted into a gas which will escape and form close pores inside the finished goods, and pores with open passages on the surface of the finished goods, such that the finished goods will have the lightweight, insulating, refractory, and water-resisting features.

What is claimed is: 
     
       1. A method of manufacturing lightweight ceramics, comprising the steps of:
 A. mixing a powdered glass material, a powdered alkali silicate, and a water-soluble polymer according to a fixed proportion to produce a dry substrate; 
 B. adding water to the dry substrate and molding the substrate into a desired shape to produce a molded substrate; 
 C. removing part of the water; and 
 D. heating the molded substrate to a predetermined temperature to form a ceramic; 
 wherein, in the heating step D, oxide and hydroxide in the alkali silicate being used to lower the softening point to the powdered glass material, and when the powdered glass material being in a semi fluid state, air and crystal water brought by the alkali silicate being expanded and forming air bubbles, the water-soluble polymer being converted into a gas and forming close pores inside the ceramic, pores with open passages on the surface of the ceramic. 
 
     
     
       2. The method of manufacturing lightweight ceramics of  claim 1 , wherein said powdered glass material is a granule of size below 50 mesh, said powdered alkali silicate is sodium silicate containing sodium oxide, sodium hydroxide, or silicon oxide, and said water-soluble polymer is dextrin, and said powdered glass material, powdered alkali silicate, and water-soluble polymer are mixed respectively in a proportion of 90%, 10% and 3% by weight. 
     
     
       3. The method of manufacturing lightweight ceramics of  claim 1 , wherein said powdered glass material is a granule of size below 50 mesh, said powdered alkali silicate is sodium silicate containing sodium oxide, sodium hydroxide, or silicon oxide, and said water-soluble polymer is dextrin with a high carbon content, and said powered glass material, powdered alkali silicate, and water-soluble polymer are mixed respectively in a proportion of 60%, 40% and 4% by weight. 
     
     
       4. The method of manufacturing lightweight ceramics of  claim 1 , wherein said predetermined temperature is 800° C. 
     
     
       5. A method of manufacturing lightweight ceramics, comprising the steps of:
 A. mixing a powdered glass material, a powdered alkali hydroxide, and a water-soluble polymer according to a fixed proportion to produce a dry substrate; 
 B. adding water to the dry substrate and molding the substrate into a desired shape to produce a molded substrate; 
 C. removing part of the water; and 
 D. heating the molded substrate to form a ceramic; 
 thereby, in the heating step D), the alkali hydroxide being used to lower the softening point of the powdered glass material, and when the powdered glass material being in a semi fluid state, the water-soluble polymer at a predetermined temperature being converted into steam and carbon dioxide gas and said gases forming close pores inside the ceramic, and pores with passages on the surface of the ceramic. 
 
     
     
       6. The method of manufacturing lightweight ceramics of  claim 5 , wherein said powdered glass material is a granule of size below  50  mesh, said powdered alkali silicate is sodium silicate containing sodium oxide or sodium hydroxide, and said water-soluble polymer is dextrin, and said powdered glass material, powdered alkali silicate, and water-soluble polymer are mixed respectively in a proportion of 95%, 5% and 10% by weight. 
     
     
       7. The method of manufacturing lightweight ceramics of  claim 1 , wherein said predetermined temperature is 800-1100° C.